Thread clamp for sewing machines



May 12, 1959 F. w. KELLS THREAD CLAMP FOR SEWING MACHINES Filed Jan. 5, 1956 United States Patent O ,t l e 2,885,985 e 1 vrunnin) cLAMPxFoR SEWING MACHINES Frank W. Kells, Jacksonville, Fla. e Y `Applicatium January 3, 1956, Serial No. 557,090 volaims. A'(Cl. i12-4253) automatically operated thread end clamping device for sewing machines, e f *Thedevice 'herein disclosed is applicable to substantially all "types of domestic sewing machines andto many types fof heavy duty manufacturing machines, is readily -adjustablefor effective operation `on any specicmachine with rwhieh it may be used, is readily attached or detached from a sewing machine, is simpleand of inexpensive construction, is sure in operation, and is locatable inta position in `which there is no interference with normal operationofthe sewing machine. e

In the operation of sewing machines of the` types pres-` ently in common `domestic` use, and similar types, considerable `threadiswasted and malfunction often occurs because the loose ends of the bobbin and needle threads during formation of the first stitch `are pulled back into the. work. The seamstress, to minimize first stitch failure,

or unthreadingodraws aboutone `foot of extra thread from` the needle and bobbin and lays these thread ends back `across the `work surface. t Even when this precaution is taken, however, thetrst stitch is likely to bebadly formed. t, t te `The device` to `which this `invention is particularly directed comprises in its preferred` embodiment` a` convenient attachment 'which mounts'on the presser foot bar of a sewing machine andwhich is operated automatically into atthread-clamping ,condition upon raising of the l t presser foot and is thereafter operated into a thread-release condition inresponse to` ensuing `motion of the needle holder assembly as stitching starts. e 1

The `novel features which are believed to be characteristic of this invention t are set forth with particularity in the appended claimsl The invention itself, however, both as to its organization and `method of operation, `together with further objects and advantages thereof, may best be understood by reference to `the following description :takenin connection `with the accompanying drawing, `in

:Which: .e i. o U A ,e t. Fig. 1` `is a perspective viewtshowtng a device 1n accord with this invention inoperative position in connection` with partially broken away` and fragmentary portions of asewing machine;

t Fig. `2 is a side elevation of the device of Fig. l, `shown Vpartially lin section, together with fragmentary representat -tion of` portions of the sewing machine with which the deyvicefis in` use, taken from the right handside and looking Qllliwardlyj` i. ,t

F Y Ice 2,885,985

Fig. 3 is an enlarged detail sectional View of the device taken along line 3 3 of Fig. 1; and

Fig. 4 is an enlarged bottom View of the `device taken along line 4-4 of Fig. 1 and showing further details thereof. e, i Referring to Fig. l, the thread clamp device comprises a generally U-shaped mounting clamp or base member 1 with a projecting support member or portion in the form of a cylindrical post 2 extending laterally therefrom. Clamp `1 is rigidly, thoughpreferably adjustably and removably, attached to the presser foot bar 3 of a sewing machine, and a pair ofthread clamping jaw members 4 and 5 engaged on post 2 are, accordingly, carried in a position generally fixed with respect to the presser foot bare A sensing or triggering arm member 6 and af conditioning arm member 7 are both attached to thread clamping` disc 5, which` is mounted on support 2 to be movable therealong through a short distance and rotatable through a few degrees. Conditioning member 7 has a lower endV loosely joined to the upper rear side of jaw member`5 and an upper end preferably in` the shape of a yoke or collar 8 loosely tting against bar 3 and arranged, upon raising of the presserfoot, to meet sewing machine headhousing 9. Trigger member 6 comprises a relatively long and thin member, preferably with sutlicient resilience to` bend without breaking. The trigger member extends `from an end attachedto the lower side of disc or jaw member 5, to the rear of presser bar 3 and curves forwardly to have a free forward end disposed, when the device is in thread-clamping condition, -in the path `of, some portion of the needle holder assembly 10. A` needle 11 is connected as apart of Athe needle holder assembly. The forward end of member 6 comprises a loop 12 to avoid catchingof work or injuryto the operator. The device as shownin Fig. 1 is operatively clamping the respective end portions of a needle thread 13 and ofa bobbin thread 14 preparatory to starting the stitching of a Work` piece 15. The needle thread, supplied fromethe usual spool and through `appropriate guides of the machine, is threaded through eye 16 of needlell and is then preferably passed through the needle slot 17 of` presser foot `18 and rearwardly under the foot to be ,woundone complete turn, or less, inthe narrow annular wedge shaped groove `existing between discs 4` and 5. A short bitter end 19 of thread 13 is shown hanging from the clamping discs. In a similar manner, the bobbin `thread 14 is brought out under the entering or rearward edge 20 of work piece 15 and its end portion is wound in a single turn, or less, in the clampinggroove along with the needle thread. `The bitter end of thread 14 is shown in typical position at 21. In operation, as needle 11 moves downwardly, some part of needle holder assembly 10, such as the lowerend 22 of needle bar 23, will strike an end portion of trigger member, at or adjacent loop 12, and, as later explained in greater detail, the resulting downward swinging movement of trigger 6 causes `the clamping disc v5 to move sud- 'denly away from disc "4, thereby to release the threads from the discs 4 and 5.

Further `details of the assembly are shown in Fig. 2, f

which is taken from the right hand side of the sewing machine head 9 looking outwardly.` Trigger arm 6 is attached rigidly by a bolt 24 to the lower side of cylindrical collar or hub portion 25 of jaw member 5 and extends generally forwardly around presser foot bar 3, shown broken away, to dispose its forward end loop or hlunted portion 12 in the path of needle mounting bar 23.

` A bolt 26 passes loosely` through a lower end slot 27 of conditioning arm 7 loosely to couple the arm. to the upper rear side ofcollar 25,-and the upper yoke portion 8 of arm 7 is `in position, upon raising of presser foot bar 3, to en- Patented May 12, 1959 l and 2. In this position, arm 6 is seen to be generally horizontal, but,upon'lowering of the needle holder assembly into the position indicated by broken lines 28, arm 6 will be triggered. by contactwith assembly 10 into the position 29 while jaw member Sawilfl rotate counterclockf wisetbrough about 3.01jto' 'SSOrlegrees on post `2 and arrn'7 wllLfiseto dispose-yoke 'Sintbe position shownin broken lines at 30. 'The bro'ken line positions of Fig. 2, aecordingly correspond to oneniaw c rthreadreleasing ,conditionfofthe .device .1.11 the tbreadzclanlpng. full line, vcondition shown in Ii g2, the threads 1,3 and14 from the needle lland from the lbob'birn grespectiyely, issue rearwardly from below presser foot Island nass vupwardly and rearwardly tothe clamping jaws- A stonmember v31l isbreferably attached to hub -25 of movable iaw `member and is engaged, or closely ap- Pr d, lby a stationary Atired carri follower member 32..,W h is rnounted to andextends outwardly from p ost 2 @am follower 32 engages f ace 33 of hub portion 2,5, and, more particularly, permits jaw member 5 `to slide along post 2 in response to rotation of the jaw member intoa rotative position to engage follower 32 in acafm notch 34 Aformed into the face 33 of the hub. 'Ihetcooperating cam means, accordingly, comprises ,follower32, notch 34and the portion 3S of -face 33 which liesgenerally between stop 31 and notch 34.

Fa`ce33 of )hub 25 may be bevelled remote lfrom the operatingppcam-portions Aas at 36 for thepurpose of proyiiding clearance with portions of the monntingciarnp or base member, thereby Vto make possible a morecompact overall structure, as will be more apparentinFig. 4.

Illig. 3shows in sectionalized rear yiew, on enlarged scale, and partially in section, details of the clamping device `which is inY thread release or open position. Bolt 2,6,.is seen to have moved upwardly, kIaising yoke 8 of arm 7 along presser foot bar 3, while bolt24 hasmoyed more toward the rear and trigger arm 6 now kslants downwardly toward its yforward end. Laterally `extendngpostaZ is locked by pin 3.7 in clamp member -1..a n.d the clamp o r base member, in turn, is removably locked to bar 3 by .means of set screw 38.

follower member 32 is engaged in the cam noteh 3.4and jaw `member 5 has movedfslightly away fromwstationary jaw member 4 toeren the thread slot 3,9 between .the jaws.. The .motion of :rotatable and .slidable iaw member 5 toward Aand away from stationary jaw retomber/fills, determined by .the resneetiyeoberations of the. earn means, including notch 34 and follower v312, :and of; aeoiled .compression spring 40d1fsposed in an. enlarged bore.- 4l of moy-able iaw member `5. Spring 40. biases,4 because it is a compression spring, inernber S away frorn member 4 whereas rotation of vinenaber 5 by earn actionl .causes sliding motionof vmember 5 to-r ward member 4 against the force of spring 40- Jaw closing ,motion of member 5 toward member 4 is attained, las heretofore mentioned, by movement upwardlyofwbar 3, lbase 1 and `members 4 and Siwhilefyoke isin contact with previously shownhead` 9of the sewing machine.l The upward movement of the several` lower parts of the clamping assembly relative to yoke 3 and mV/'i5 ,Such ,tocause holt Z6 to move, with resultant rotation ,of Ymember15, into a position` more nearly 'behind,zr atl1er-than. above, post 2.

The hub 25 of finember 5 isxpreferably engaged on -post 2, with a tsuiicientlytight -to ,providefric-tional resistance to rotation of member 5 on post Y2, and the inner sur.- faQe-,ig of hubv 2,5eng-aging outer surface 43 of post 2 comprise means yfor restraining member 5 against-rota,- tionV Lfrom its closed-jaw -to its open jaw positions. Jaw member ,4-isl :eyedy or locked to the `end of post 2 ,by meansoa' mall key or pin 44and comprises a collar onnel portion-1,45 which fits within enlarged bore-41y of member ,5. Aegordingl friction between neck` portion 45and; h1l1IfQexQbore41 may; also restrain rotation of member 5, and these portions of the lassembly comprise means for restraining` rotation o'f member '5' from its closed jaw position.

The ends of spring 40 are preferably turned outwardly and engage in sockets, the end 46 being inserted into socket 47 in hub 25 of member 5 and end 48 being inserted into a socket or slot 49 formed in member 4. Spring 40 may be lso tensioned -between its ends as to urgezmernber 5 to rotatevinteitherfdesired direction, Ywhereby the spring may serve not only its primary function of biasing member 5 Aslidingly away Vfrom member 4, but also one Vor another of vtwo additional functions. Speciiically, the spring may urge the member 5 to rotate toward the position in which cam follower 32 engages in notch 34 or it may be adjusted to tend to oppose rotation of member 5 toward this position. If spring 40 is ladjusted to urge member 5 to rotate into the .position in which .follower 32 i engages the, notch, the springwyill function to impart snap action, `upon triggering by ger `arm vtifinto the iaw openuposition of iaw member ,5- Such` -adjustmentof spring 40 is` desirable where .other means for restraining* Amember 5 in .its jaw .closed position areadcquate. Howeven-ifjaw member-5 -tends readily to rotate into ,released position, ther spring beadiusted te-assist, .rather than 'to oppose, the restraining` friction of members -on post 2. p

Bolt .570 attaches stationary jaw member `4 rigidly the end of ,post 2 but by slightly loosening the bolt, untilfmeniberimoyes. outwardly sutciently 'todisengage pin 44, member 4 may be rotated to wind or spring ft-and thereby to adjust the spring to oppose or assist, lonrnore or 'less to oppose orv assist, `rotation of meinber towardits `jaw opening rotatiyetposition- Jaw .rnember4 ,preferably comprises a .generally shaped,member vsuiciently thin `to-,haye some resilience. Sueli .resilience improvesv the clamping actionA of the iawsfonf-threadof varying sizes- :It will be apparent that theepr-esenee of. threads ,in the notch `31.9 will tinereaseftlie frictional resistance to rotation ofmember 5 from-dosed iaw Aposition toward open jaw position.

. It will be further apparent,"particularly-withtreference totfliig- 4J that engagement of cam follower 32 :with the surface Portion `3.5, with which itis in Ycontact -i-when the `:jaws are in Yclosed v,or clamping posi-tion, flicticnally obnoses `rotation of iaw member 5 rinto. its open inw position shown in Eig- 4 'Izbe cam. follower 32. and surface portion 35, accordingly, function; as, means: ,tto in rotation ofjaw member 5 `fromits jawopmlto its flew, .closed position. The flictional force between follower 32 and surface portion 35 will depend :upon thecsmoothnes's or roughness of surface portion 35, on the materials employed, and ,on other well .knownacr tors and various vmeans of increasing resistance-ito` tionvfromthe closed jaw position -of member .5 will be apparent to those skilled in the art. It should 'be .underfstoodthat it :is -most desired to` oppose the sta:1'.tingoin'o tation` of the, movable jaw member from` itsy awt-iclosed 1 position, and that, accordingly,lit ispIeerredthattthe static, friction, or static` resistance to Yrotation from the jawmclosed position, should be, `as `it: normally would tend to be, somewhat higher than' the sliding l1lrictionuor resistanceimmediately after rotation has 'been started or triggered bythe-striking of .arm .6 by-theineedle :holder assembly 10. Y

'.-The view `of Fig. 4, showing the ,device ffrombelow, may be compared with the previously described flgures for atmorebomplete'understanding .of-"the shape ofiitrigger ..6 and, its positions. 'Ilhe arm 6 vis Ashown in Eig. infull llines .in i-ts position corrcspondinglrtotthe illustrated open jaw condition of the clamping device; whileffthe rbroken yline position correspondsr to rthe 'closed jawrcondition. 'Ihe .clamp for base member 1 lisifunther seen. :to be attached `byset Ascrewr38 to presser- `foot ibm 3, .andarmvpassestothe rear .of bar. Garn follower 32 is engaged in cam notch 34, and the position ofstop 31 which projectsfrom face'133 isclearly shown.l )Bevel A notchSZ may be providedin stationary jawlmember #with one` or more sharp cutting edges fSSforconvenience in cutting threads, `for example, `atl the end of each sewing operation. Notch 52 is also seen inA Fig. -1.

In several instances, parts f of the device are-.identified in one of the yfigures without specific discussion. In such instances, the description applicable to some other figure applies' equally, since identifying numerals are consistently employed throughout the several figures to assist in comparisonstherebetween. It will be'lunderstood, however, that the device is shown in full -lines in Figs. 1 and 2 in its jaw closed condition, while the full line views of Figs. 3 and 4 correspond to jaw open or thread release condition.

While only certain preferred embodiments of this invention have been shown and described by way of illustration, many modifications will occur to those skilled in the art and it is, therefore, desired that it be understood that it is intended in the appended claims to cover all such modifications as fall within the true spirit and scope of this invention.

What is claimed as new and what it is desired to secure by Letters Patent of the United States is:

1. A thread end holding device for a sewing'machine,

said device comprising a presser foot bar mounting clamp, a support member extending laterally from said clamp, a thread engageable member movably mounted on said support member, a spring in contact with and urging said thread engageable member into a thread releasing position, means to twist said thread engageable member in a predetermined direction of rotation into a thread clamping position, said means comprising a sewing machine head engageable arm attached to said thread engageable member, said thread engageable member and said support member being frictionally related whereby said thread engageable member is restrained by friction in said thread clamping position against the force of said spring, and means attached to said thread engageable member extending into the path of a portion of a needle and needle bar assembly of the machine operable to impart friction-releasing motion tosaid thread engageable member in a direction of rotation opposite to said predetermined direction in response to contact therewith by said portion of said assembly.

2. A thread holder comprising a generally U-shaped clamp member having a projecting portion, a jaw member fixed to said clamp member, a second jaw member rotatably mounted on said projecting portion of said` clamp member and slideable therealong in directions toward and away from said iixed jaw member, a spring engaging between said clamp member and said rotatable jaw member urging Said rotatable jaw member in the direction away from said fixed jaw member, cooperating cam means on said rotatable jaw member and said clamp member effective to force said rotatable jaw member toward said fixed jaw member in response to predetermined rotation of said rotatable jaw member, a sewing-machine-o head-engageable arm joined to and extending from one side of said rotatable jaw member effective upon raising of said clamp member toward said head to rotate said rotatable jaw member in said predetermined rotation, and a sewing-machine-needle-assembly-engageable arm joined to and extending from a 1generally opposite side of said rotatable jaw member effective upon engagement there- Ywith by the needle assembly to cause opposite rotation of said'rotatable jaw member.

3. A thread end clamp for a sewing machine comprising attachment base means mountable on the presser foot bar of the sewing machine, a post extending from said means, a first stationary jaw member and a second rotatable and slideable jaw member both mounted on said post, `a surface on said' second'ja'vviir'ieniber1 anda* cooperating cam `follofwer forming as'tationary part of.

said post, a spring having one `end fixed` to-said post fand another end engaging said second jaw member andfbiasing said second jaw member in a slidable direction alongv said post away fromsaid first jaw member, said camsur-` face and follower being disposed and engaged to force said second jaw member toward said first jaw member `in response to a predetermined rotational movement inea" predetermined direction of said second jaw member, and

arm means extending outwardly from said second jawV member for rotatingsaid second jaw member `through said predetermined rotational movementrin said `predeterin response `to contacts thereof by, respectively, the head and alternately by the needle holder assembly of the sewl ing machine.

4. In a thread clamping device, a post, a stationary jaw member rigidly connected to said post, a second jaw member, means rotatively and slideably mounting said second jaw member on said post, cooperating cam means on said post and one said second jaw member establishing respective jaw open and jaw closed rotational limit positions of said second jaw member, at least one of said means comprising means frictionally opposing rotation of said second jaw member from said jaw closed position, a spring engaged between said jaw members biasing said second jaw member slidingly away from said first member, said cam means sliding said. second jaw member against said spring bias toward said first jaw member in response to rotation of said second jaw member from said jaw open limit position to said jaw closed `limit position, and means attached to said. second jaw member and extending outwardly therefrom to rotate said second jaw member from one to the other of said limit positions.

5. A thread end holding device for a sewing machine comprising a base member, a stationary jaw member mounted on said base member, a movable jaw member movably supported on said base member, means urging said movable jaw member into open position, releasable means to restrain said movable jaw member in closed position, a pair of operative actuating elements coupled to said movable jaw member adapted and arranged to be contacted by respectively different portions of the sewing machine which are movable with respect to said base and with respect to each other, one said element moving said jaw member in one direction in response to contact thereof with one of said portions to close said jaws and the other said element comprising trigger means operative in response to contact of said other element with another of said portions to release said movable jaw member from said restraining means.

6. A thread holder for a sewing machine comprising a base member having a stationary jaw member affixed thereto, a rotatable movable jaw member, means to move said movable jafw member toward and away from said stationary jaw member in` response to rotation of said movable jaw member in respectively opposite directions, and a pair of arms coupled to said movable jaw member adapted and arranged to contact respective relatively movable parts of said sewing machine and operative respectively to rotate said rotatable ja'w member in respective directions in response to said contact -With said respective relatively movable parts.

7. A thread end holding device for a sewing machine having a presser foot bar, a needle holder assembly and a head, said device comprising a base adapted to be clamped to said presser foot bar and movable therewith, a movable jaw member movably mounted on said base, a stationary jaw member fixed to said base, an element attached to and extending from said movable jaw member arranged to contact said head upon partial raising of said presser foot bar and to move said movable jaw member relative to said base from a jaw open positionI spaced fromsaid stationary avy y,member to ,a jaw closed.

position thereon ecjacent said stationary jaw member upon frthejr;,raisingjpfsaidrpresserfootrbar; aspringw ing. restraining means connecting said, movable jaw merlinV ber "and sai` base 'when said movableV jaw member reaheslsaidijaw 'closedv position and effectiveto retainv saidmovable, jaw member in said jaw elosed position againstl said spring force; and releasingl means comprisin'g an arm 'coupled to said portion-of said movable jaw memberad `extening Iinto the path of said needle holder portion of vsaidass'embly andv operativev upon 'eontat thereof by saidassembly .ttteleasve saidrestrainingzfmeansi. therebyJf/torgeause said` mmableihwnmemben to bmoved; from f segidf segz'ondey spring; said. jaw. members being effective to clamp a threadlend-.thuel-: betweem saridqmovabl memben-. is? inf? :miek` j llw closed' Apositionn` andfyto release` said. 'clueadf end; upon?! movementpoelsaide movable jaw member .frompsaidf close@ position. v l l l nemeeegoifealm theme finie patera# 

